Means for thermostatically controlling gas fired heaters and the like



May 5, 1942.- c. R. ROBERTS 7 2,281,519

MEANS FOR THERMOSTATICALLY CONTROLLING GAS FIRED HEATERS AND THE LIKE 1 Filed Feb. 15, 1959 v Inventor a iz flobkris' I A itorricys Patented May 5, 1942 UNITED STATES PATENT; OFFICE MEANS FOR THEBMOSTATICALLY CON- v TBOLLING GAS FIRED HEATERS AND THE LIKE cumin! a. n wts, Brighton, Mich. 2 {Application February l5, 1?, Serial No. 256,605

4 Claims.

My invention relates to a method and apparatus for thermostatically controlling gas fired heaters and the like, in which the usual alternatable hum and chatter which usually obtains where alternating current is applied to devices of this general character. I

Other important objects and advantages of my invention will be apparent from the reading of the following description taken in connection with the drawing, wherein for purposes of illustration I have set forth a preferred embodiment of my invention.

In the drawing:

The single view is a schematic wiring diagram showing an arrangement in accordance with the present invention.

Referring in detail to the drawing, the numerals I and 2 designate the respective wires of an A. C. input line, the wire I being connected to the point 3 of the thermostat 4 which is electrically connected to the contact point 5. If by action of the bimetallic element this contact 5 is made to touch the contact point 6 which is connected by the wire I to the transformer primary coil terminal 8, the other input wire 2 being connected to the primary coil at the terminal 9, a

' complete electrical circuit is established and a high voltage is induced in the secondary S-l and this voltage appears at the terminals II and IS. The terminal II is connected by the wire l2 to the terminal l3 of the electronic rectifier or vacuum tube It. The terminal I1 is connected by the wire i311, sealed in a glass tube, to the electrode I 3b. The terminal I! is connected by the wire l6 to the terminal l1, and the terminal I! is connected by the wire Ila, sealed in a glass tube, to the electrode 11b, the terminal I! being connected by the wire is to a common negative ground.

The secondary winding 5-2 of the transformer consists of comparatively few turns of wire and, therefore, produces a relatively low voltage which appears at the terminals and 2|. A wire 22 connects the terminal 20 with the terminal 23 of .the rectifier tube I4, and the terminal 2| is. connected by a wire 24 to the terminal 25 of the tube It. A wire 28, sealed in a glasstube in the rectifier tube is connected between the terminal 25 and the terminal 21 and the wire 28, also sealed in a glass tube in the rectifiertube but insulated from the wire 28, is connected between the terminal 22 and the terminal 29. Within the vacuum tube I4 is astrip of metal or other suitable material to form a filament which completes the circuit between the terminals 21 and 29, and the resultant flow of current heats the filament 20 to redness causing electrons to be driven off therefrom. These electrons appear to be negative and alter the internal resistance of the vacuum tube It.

With respect to the secondary 'Sl of the transformer, the electrodes lib and 11b of the vacuum tube being connected to the secondary terminals H and I5 respectively of the trans-- former It, the electrodes llb and "b are at opposite polarities at all times. In" other words, if the electrode I 312 is positive, the electrode "b will be negative and vice versa.

In view of this electrical condition, it is evi-- dent that while the electrode llb'is positive, current will flow toward the hot filament 22 but no current can flow from the electrode IIb which is-then at a negative polarity. The terminal it of the transformer I0 is then also negative to the electrode l3b but at a potential of about one-half of the original voltage, due tothe fact that the terminal l8 subtends only at one-half of the total number of turns of the transformer secondary winding S- -l. This situation exists during one-half of each cycle. In the second half of the alternating current cycle, the electrode IIb becomes positive and the electrode 13b becomes negative, so-that current flows from the electrode llb toward the hot filament,

but the repellent action of the negative electrons emitted by the hot filament prevent any current flowing from the negatively changed electrode 13b, so that the electrode I'Ib supplies a positive voltage to the terminals 22 and 25, inclusive, with the terminal l8 remaining negative. This arrangement produces a pulsating direct current voltage at approximately one-half the total secondary-voltage between the terminal 18,- or any position along the wire l9, and either terminal 23 or 25, inclusive.

The wire 3! is connected to the terminal 23 and extends to and is connected to the terminal 32, another wire 33, connected with the wire 3|, is connected to the terminal 34 of the condenser 35, and the terminal 38 of the condenser 35 is switch coil 39. The

the wire 4| to the negative wire IO, thereby completing the circuit through H r a The function of the resistance unit 31 is to of a solenoid valve.

definitely a factor in unit 41, which is normally,

1 the output of the rectifier l4 and furnishes the conventional filtering action by removing the pulsations or ripple from the output of the rectifier, thereby producing a practically ripple-free direct current. voltage. affixed a resistance unit 31 which is connected to the terminal 35 of the relay or magnetic terminal 40 is connected by the coil 39 regulate the amount of current flowing in the coil 39. In operation the relay which is electrically connected to the terminal 52 at one end and has contact points 43, 44, respectively, at

the movable end thereof should not change con tacts until the voltage from the rectifier has reached a predetermined value slightly less than maximum. Rectifiers which depend on a heated filament for operation have a gradually increasing current period of the filament, which gradually increasing current is unsatisfactory for the operation However, it the action of the relay armature 42 be adjusted by regulating the current in the coil 39 so that the armature will operate at a voltage only slightly less than the maximum output of the rectifier, the resultant sudden application of this voltage to the solenoid coil 49 produces a quick, jerking action on the valve 55, and makes it possible to use a lower voltage and current in the solenoid coil, with consequently less heating effect and ,waste of current. The snap action of the relay is the efllcient operation of the system as a whole. During the off period and until a certain predetermined voltage is attained, the contact points 43 and 45 are engaged or closed. The contact point 45 is connected by the wire 45 to the resistance unit 41, and the wire 48 connects the remaining side of the resistance unit 41 with the wire I8, thereby estab-- lishing a complete circuit through the resistance or during the off period included in the output circuit of the rectifier of equal or preferably higher value than that of the solenoid coil 49. This condition exists during the heating period of the rectifier filament. However, when nearly the maximum voltage as mentioned above is obtained,.therelay coil 39 is sufliciently energized to attract the' armature 42 and thereby separate the contacts 43 and 45, thereby removing the resistance 41 from the circuit and simultaneously closing contact points 44 and 50 connecting the solenoid 49 in the same relation in the circuit as priorly occupied by the resistance 41. The solenoid coil 49 then receives the ripple-free direct current that priorly passed through the resistance 41, the said resistance being now inactive.

The contact point 50 is connected by'the wire 5| to the terminal 52 of the solenoid coil 49, and the remaining terminal 53 of the coil- 49 is connected to a wire l9 which is connected to the center tap IE or the secondary winding Sl of the transformer l0, whereby-a complete circuit through the solenoid coil 49 is established, whereby the armature or plunger 54 is drawn upwardly and the lifting valve head 55 is moved from its seat, 'so as to allow gas to pass through the valve body to the heateror burner until enough heat has been generated to cause the thermostatic element of the thermostat 4 to open To thetermlnal 34 is,

output characteristic the heating the contacts and 6. When the contacts 5 and 5 open all circuits become dead, and the valve head is allowed to return to its seat by force of gravity, and the relay armature 42 returns to its original position by reason of the action of the spring 42a, thereby causing the contact points 44 and 50 to open and re-establish the engagement between the; contact, points 43 and 45. This condition obtains and is sustained until such time as the thermostat is actuated by a temperature below that for which it is set, when the cycle of, operation described above is repeated automatically.

Although I have shown and described herein a preferred embodiment of my invention, it is to be definitely understood that I do not desire to limit the application of the invention thereto, and any change or changes may be made in the structure and arrangement of the parts, within the spirit of the invention and the scope of the subjoined claims.

Having described the claimed as new is: 1

1. In combination, a source of alternating current, an electronic rectifier tube, an electromagnetic switch having a single pole double throw element, said electromagnetic switch having one end of its movable arm connected, by wire, to one terminal of the said rectifier tube, the opposite end, of said movable arm being provided with suitable contact points for alternately coninvention, what is necting and disconnecting a phantom load clrcult and a bona fide load circuit to the direct current output of the said rectifier tube, the said phantom load circuit and the said bona fide load circuit not being connected to the said'rectifier tube circuit simultaneously, the said movable arm being so constructed that simultaneous connection of two circuits is prevented, the said electromagnetic switch to become operative at a predetermined voltage whereby the movable arm is made to change from one position to another position under the magnetic influence of an op- .erating winding, said winding being of high resistance and connected, by wire, across the output of said rectifier tube, the said movable arm, upon deenergization of said operating winding, is made to change from one position to another position by the influence of a spring attached thereto, the said spring action providing a means for disconnecting the bona fide load circuit and providing for connecting the-phantom load circuit to the direct current output of the said rectifier tube, the returns of said circuits being connected, by wires, to the mid tap of a supply transformer whose opposite ends of a secondary winding are connected, by wires, to the two anodes of said electronic rectifier tube, the oathode element of said electronic rectifier being considered as output terminal.

2. In combination, a source of alternating current supply, a transformer, a thermionic rectifier tube, anelectromagnetic relay switch, said electromagnetic switch to comprise amovable element operable in two positions, a resistance unit to supply an artificial loading efiect in the electronic tube circuit, said load to be eilective dur-,

ing the heating period of the said electronic rectifier tube filament, the said electromagnetic switch being provided with suitable contact points for disconnecting the said artificial load when a predetermined voltage is attained in the rectifier tube and, bymagnetic influence of anoperating winding, applying said voltage to' a bona fide load circuit, the said contact points ing the full alternating current voltage appliedto its anodes simultaneously with the filament voltage, the said direct current being filtered by a conventional condenser connected, by wire, across the output terminals of the said electronic rectifier tube.

3. In combination, a source of alternating current, a rectifier tube, a resistor for loading-said rectifier tubecircuit during the heating period of the said rectifier tube filament, a condenser for filtering the pulsating direct current output of the said rectifier tube, an electromagnetic switch having an operable winding connected, by wires, across the filtered direct current output of the said rectifier tube, said electromagnetic switch being supplied with a movable element having -uitable contact points for making connection to specific circuits alternately and at no time simultaneously, the said movable element being magnetically operated and electrically connected to one output terminal of said rectifier tube, said contact points being so adjusted that the said resistor will be normally in series with the rectifier tube elements until a predetermined voltage value is attained by magnetic influence, said contact points being caused to separate so as to eflect isolation, electrically, of the said resistor, the said magnetic influence, still in evidence, eflecting the closing of a difierent set of contact points, these said contact points effecting the connection of a bona fide load circuit by application of the full voltage, of the filtered direct current, thereby obtaining an instantaneous'action, the said movable element, being held in the normal or warming position by a spring,

' ionic rectifier having 3 which, upon de-energization of its operable winding, returns to said normal position by spring action, the said spring action efiecting the disconnection of the bona fide load circuit, and in the same motion, effecting the connection of the loading resistor to the direct current circuit, the said instantaneous actionbeing efi'ective in the bona fide load circuit.

4. In combination, a source of alternating current, a transformer, a thermionic rectifier, a loading resistor, a single pole double throw switch electromagnetically operated from said'thermionic rectifiers output, said electromagnetic switch supplying a means for disconnecting said loading resistor from the thermionic rectifier circuit, also supplying a means for connecting a bona fide useful circuit to said thermionic rectifiers output, said connection means being caused automatically by a predetermined voltage obtained from said thermionic rectifier, said therma condenser bridged across its terminals for conventional filtering of the pulsating direct current, said switch providing a means for disconnecting said bona fide load circuit and supplying a means for connecting said loading resistor circuit, de-energization o! the circuit allowing said switch to be controlled by a spring, said spring providing for action opposite to the action caused by the direct current voltage, saidswitch providing for no simultaneous connection to the thermionic reotifiers output circuit of the loading resistor and the bona fide load circuit, the said bona fide load circuit being disconnected from the said output circuit during the heating period of the thermionic rectifiers cathode] CLIFFORD R. ROBERTS. 

